D5R2 and D6R2 Track-Type Tractors Power Train Oil Temperature Is High Caterpillar

Personal injury or death can result from escaping fluid under pressure.
Escaping fluid under pressure, even a very small pin-hole size leak, can penetrate body tissue and cause serious injury and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury.

Always use a board or cardboard when checking for a leak.

Probable Causes

Power train oil level is low
The power train oil cooler has leaks
The power train oil contains a large amount of air
The temperature gauge is not operating properly.
The power train oil cooler is plugged.
The fan motor is not operating properly
The scavenge screen is obstructed. There is a large amount of oil.

Recommended Actions

Note: Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the machine. You must be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component that contains fluid. Dispose of all fluids according to local regulations.

Power Train Oil Level Is Low

Ensure that the power train oil level is in between "OPERATING ZONE" marks on the dipstick. Refer to Operation and Maintenance Manual, "Power Train Oil Level - Check".

If the oil level is low proceed, to "The Power Train Oil Cooler has Leaks" to determine if the power train oil is leaking.

The Power Train Oil Cooler has Leaks

Inspect the oil and coolant reservoirs on the machine and perform an SOS analysis to determine if there is cross contamination between the systems.

Thoroughly examine all surfaces, tubes, and connections on the power train oil cooler for signs of leaks. If oil is leaking, dirt and dust will adhere to the oily surfaces more than dry surfaces. Tighten any loose connections or fittings that might be leaking and recheck for leaks. The power train oil cooler should be replaced if there are leaks on surfaces in addition to the fittings.

Note: Be sure to differentiate between coolant that may be leaking and oil that may be leaking. The odor may help to make this determination.

The Power Train Oil Contains A Large Amount Of Air

Obtain a power train oil sample.

The sampling valve for the power train oil is located on the power train oil filter on the left side of the machine. Refer to Special Publication, SEBU6250, "Fluid Recommendations for All AVSpare Machines, S·O·S Oil Analysis" for information that pertains to obtaining a sample of the power train oil. Refer to Special Publication, PEHP6001, "How To Take A Good Oil Sample" for more information about obtaining a sample of the transmission oil.

Check the hydraulic lines and check the fittings on the inlet side of the power train oil pump for leaks. Air may be drawn into the system from the suction side of a circuit during operation if the lines, hoses, or connections are damaged.

The Temperature Gauge Is Not Operating Properly

The sensor outputs a voltage signal that corresponds to the temperature of the power train oil. The voltage signal is input to the Machine ECM. As the temperature of the power train oil changes, the resistance of the sensor changes. As the resistance of the sensor changes, the indicator for the power train oil temperature in the instrument cluster will change.

Inspect the temperature sensor for proper operation.

Repair the components and/or replace the components, if necessary.

The Power Train Oil Cooler Is Plugged

Check for restrictions in the oil cooler lines.

Check for restrictions in the cores of the oil cooler.
Inspect the internal components of the power train oil cooler for contamination. Contamination may create a blockage or restriction between the copper tubes in the cooler core. Contamination inside the copper tubes comes from coolant contamination. Coolant contamination may restrict the coolant flow through the small copper tubes that will render the cooler inefficient. Coolant contamination can also leave a residue buildup on the inside of small copper tubes in the power train oil cooler.
Inspect the external components for any contamination buildup. The external buildup is due to oil contamination. Oil sludge can leave a coating on the exterior of the copper tubes.
In either of these situations, the residue or the sludge buildup can act as an insulator to heat transfer that will render the cooler inefficient. If a residue buildup occurs between the copper tubes in the cooler core, oil flow around the copper tubes will be diminished. The diminished flow will greatly reduce the efficiency of the cooler. If the cooler becomes inefficient, the overall temperature of the power train oil will increase.

Repair the components and/or replace the components, if necessary.

The Fan Motor Is Not Operating Properly

Measure fan pump pressure with a hand gauge to determine if there is a problem with the fan motor.
The fan pump pressure reading should be ≥ 17237 kPa (2500 psi) at the top three engine speed settings.